Cytomegalovirus (CMV) infection is a common cause of morbidity and mortality in the immunocompromised patient, and as such rapid laboratory diagnosis of CMV is imperative. The shell vial method of virus culture has supplanted conventional tube culture as the primary means of detecting CMV, as the shell vial enables detection of a positive result within 24-48 hours, compared to an average of 10 days to 3 weeks for conventional culture. Because CMV is such a highly cell-associated virus, it was thought that disruption of cells in blood and urine specimens would release virus and thus enhance the efficiency of the culture. This study will compare culture results of specimens which have been sonicated to release cell-associated virus from cells prior to inoculation of the shell vial vs. unsonicated specimens, and will examine whether sonication helps to increase the number of positive culture results and/or decreases the time it takes the culture to become positive.